[VDPAU] [PATCH] Enable Lossless Decode Capabilities via VDPAU API

[Jose Soltren]

Thanks Karthik.

We were hoping to get community feedback on a few items here:

1. Name. Is there a preference for calling the new structure VdpPictureInfoH264Extended versus VdpPictureInfoH264Hi444PP ?

2. Versioning. Is there a preference to make this a versioned structure or not? Aaron Plattner expressed a preference for not making this versioned; I'll let him explain why here.

3. Containment. Should VdpPictureInfoH264Extended contain an entire VdpPictureInfoH264, or simply a pointer to one?

4. Flags. Are there any opinions on accepting values greater than 1 for transform_bypass for internal use, or should we write these into the specification? NVIDIA video decoding hardware contains a mode to work around the recently-fixed ipred8x8 bug in x264; the NVIDIA driver would accept a value of 2 to enable that workaround.

5. Scope. If this change really adds VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE, it will also need to add anything else related to Hi444PP, not just lossless decode. Namely it would need to introduce separate color plane coding, 4:4:4 chroma subsampling (a misnomer; not subsampling at all), and bit depths up to 14 bits per sample. If we choose to make VdpPictureInfoH264Extended versioned we can add those in a follow-on change. If not, we need to add those now.

We discussed this some internally, and the discussion was moving in this direction:

- it is fair to add a new picture info structure for a new profile;

- picture info structures should not be versioned (they're not now);

- thus we should do the additional work up front to add all API data for Hi444PP, even though NVIDIA hardware does not support many of them;

- the VdpPictureInfoH264Extended structure should contain an entire VdpPictureInfoH264 and not a pointer to one.

Again, suggestions welcome. We're hoping to have this applied by mid-December.

Thanks,
--José

-----Original Message-----
From: VDPAU [mailto:vdpau-bounces at lists.freedesktop.org] On Behalf Of Karthikeyan Sreenivasan
Sent: Monday, November 24, 2014 7:20 PM
To: vdpau at lists.freedesktop.org
Subject: [VDPAU] [PATCH] Enable Lossless Decode Capabilities via VDPAU API

The proposed patch will add a new struct VdpPictureInfoH264Extened, which enables lossless decode capabilities via VDPAU API.

The new struct VdpPictureInfoH264Extened contains the transform bypass flag which will enable lossless decode.

Note : For transform_bypass, NVIDIA driver will accept a value of 2 for the ipred8x8 workaround.

The patch also adds new profile
VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE (currently only with 8 bit depth support).

Videos of VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE profile must use VdpPictureInfoH264Extened.

--------------------------------------------------------------

diff --git a/include/vdpau/vdpau.h b/include/vdpau/vdpau.h index 4444de3..e6dd3ae 100644
--- a/include/vdpau/vdpau.h
+++ b/include/vdpau/vdpau.h
@@ -2445,6 +2445,9 @@ typedef uint32_t VdpDecoderProfile;  #define VDP_DECODER_PROFILE_H264_PROGRESSIVE_HIGH
((VdpDecoderProfile)24)
 /** \hideinitializer */
 #define VDP_DECODER_PROFILE_H264_CONSTRAINED_HIGH
((VdpDecoderProfile)25)
+/** \hideinitializer */
+/** \brief Support for 8 bit depth only */ #define 
+VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE
((VdpDecoderProfile)26)

 /** \hideinitializer */
 #define VDP_DECODER_LEVEL_MPEG1_NA 0
@@ -2764,6 +2767,11 @@ typedef struct {
  * Note: References to "copy of bitstream field" in the field descriptions
  * may refer to data literally parsed from the bitstream, or derived from
  * the bitstream using a mechanism described in the specification.
+ *
+ * Note: VDPAU clients must use VdpPictureInfoH264Extended to describe 
+ the
+ * attributes of a frame being decoded with
+ * VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE.
+
  */
 typedef struct {
     /** Number of slices in the bitstream provided. */ @@ -2831,6 +2839,35 @@ typedef struct {
     VdpReferenceFrameH264 referenceFrames[16];  } VdpPictureInfoH264;

+#define VDP_H264_EXTENDED_VERSION 0
+
+/**
+ * \brief Picture parameter information for an extended H.264 picture.
+ *
+ * Note: VDPAU clients must use VdpPictureInfoH264Extended to describe 
+the
+ * attributes of a frame being decoded with
+ * VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE.
+ *
+ * Note: The transform_bypass field is only valid with
+ * VDP_DECODER_PROFILE_H264_HIGH_444_PREDICTIVE and above.
+ *
+ * Note: software drivers may choose to honor values of
+ * transform_bypass greater than 1 for internal use.
+ */
+typedef struct {
+    /** This field must be filled with VDP_H264_EXTENDED_VERSION. */
+    uint32_t struct_version;
+    /** \ref VdpPictureInfoH264 struct. */
+    VdpPictureInfoH264 *pictureInfo;
+    /** Copy of the H.264 bitstream field.
+     *
+     *  0 - lossless disabled
+     *  1 - lossless enabled
+     */
+    uint8_t transform_bypass;
+
+} VdpPictureInfoH264Extended;
+
 /**
  * \brief Picture parameter information for a VC1 picture.
  *

--
Karthikeyan S | nvpublic
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